5o8 



NA TURE 



[March 31, 1898 



PHYSICO-CHEMICAL RESEARCH 



Arbeiten des physikalisch-chemischen Instituts der Uni- 

 7iersitdt Leipzig aus den Jahren 1887 bis 1896. Col- 

 lected and edited by Prof. W. Ostwald, Director of 

 the Institute. Four vols. Pp. x + 556 ; iv + 496 ; 

 iv + 656 ; iv + 550. (Leipzig : Engelmann, 1897.) 



THE year 1887 may be regarded as a red-letter year 

 in the history of physical chemistry, for it was 

 then that the birth of the theory of electrolytic dissocia- 

 tion took place. 



Although the osmotic theory of solutions is somewhat 

 older, it was also in 1887 that van 't Hoff published his 

 classical memoir on the role of osmotic pressure in the 

 analogy between solutions and gases. 



These two theories, taken in conjunction with the law 

 of mass action, form the starting-point of a new era in 

 physical chemistry, and have thrown an entirely new 

 light on miscellaneous facts taken from all domains of 

 chemistry and physics. 



The correlation of apparently isolated phenomena, 

 which was then for the first time rendered possible, has 

 materially advanced the study of philosophical chemistry. 

 Concurrently with the publication of these theories, 

 Prof. Ostwald was transferred from Riga to the Uni- 

 versity of Leipzig, where he, assisted by numerous 

 students of all nationalities, at once began the further 

 investigation and application of the new and powerful 

 weapons which had just been added to the armoury of 

 the chemist. 



An idea of what Prof. Ostwald has accomplished may 

 be gathered from a perusal of the volumes now before 

 us, representing only a selected portion of the work 

 which has emanated from his laboratory during the past 

 nine or ten years. 



In all, the four volumes contain reprints of 104 papers 

 published in the Zeitschrijt fiir physikalische Chemie, 

 which, by the way, was also founded in 1887. In many 

 respects the papfers are remarkable ; not only are many 

 of them classics, but they embrace nearly every depart- 

 ment of chemistry. We are tolerably well acquainted 

 with the specialisation which takes place in most of the 

 continental laboratories, and we are often wearied with 

 a harvest of papers all deajing with minute details and 

 with different aspects of one and the same subject. 

 This of course is necessary and important, but it is 

 none the less tedious. 



The volumes which are now brought under our notice 

 form, on the other hand, a refreshing change ; the 

 majority of the papers are of fundamental importance, 

 and are an eloquent tribute to the power and versatility 

 of the leading spirit. 



The occasion for their issue was the opening, at the 

 beginning of the present year, of the new Physico- 

 chemical Institute at Leipzig. In collecting the pam- 

 phlets for re-issue, the chronological order of publication 

 has wisely been departed from, in order, by arranging the 

 articles under their appropriate headings, to produce a 

 jnore or less homogeneous budget, and thus to facilitate 

 a general survey of the gradual development of each 

 branch. » 



The contents of the first volume are classified into 

 sections headed : general, the electrical conductivity of 

 NO. 1483. VOL. 57] 



dissolved substances, and the electrolytic dissociation of 

 acids and bases. 



The advantages of this arrangement are obvious. By 

 bringing together closely allied investigations, a great deal 

 of time is saved and misconceptions are often prevented. 

 The second paper in the volume, for instance, contains 

 the diagrammatical description of Ostwald's famous 

 experiment which is intended to remove the last doubts 

 as to the validity of the assumption of free electrically 

 charged ions. This experiment, it may be remembered, 

 consists in bringing a negatively charged body up to an in- 

 sulated vessel filled with a solution of potassium chloride, 

 and connected by means of a siphon with a similar vessel 

 at a little distance. If the siphon be now removed and 

 then the charged body, there will be an excess of posi- 

 tively charged potassium ions in the adjacent vessel and 

 negatively charged chlorine ions in the other. By con- 

 ducting away the electricity the potassium, for example, 

 assumes the ordinary form, and acting on the water 

 present develops hydrogen, which can be collected in 

 suitable apparatus and tested. This experiment has, 

 in these columns and elsewhere, given rise to a great 

 deal of unnecessary controversy which would probably 

 never have been printed if the critics had been aware 

 of the existence of the next important paper in the 

 volume, namely, that on free ions, where the imaginary 

 experiment was actually put to the test and found to give 

 results in harmony both qualitatively and quantitatively 

 with what had been predicted. 



The second volume contains chapters on homogeneous 

 and heterogeneous equilibrium, velocity of reactions and 

 the determination of molecular weights ; including a great 

 many of the original papers by Beckmann and others on 

 the theory and practice of the ebullioscopic and cryo- 

 scopic methods now universally employed. 



Volume iii. deals entirely with electro-chemistry, and 

 contains some of the most important recent contributions 

 to our knowledge of this interesting branch. Contact 

 electricity, the theory of the galvanic cell, with applica- 

 tions, and polarisation are treated of. Nowhere, perhaps, 

 have the modern theories led to such brilliant results as 

 in the department of electro-chemistry. It may be some- 

 what invidious to mention any investigation in particular ; 

 but, now that we are accustomed to look on the galvanic 

 battery merely as an engine driven by osmotic pressure, 

 we cannot allow this opportunity to pass without alluding 

 to Nernst's classical memoir on the osmotic origin of the 

 current. 



The last volume of the series, besides several miscel- 

 laneous articles, contains an account of investigations on 

 viscosity, diffusion, and optical and thermal phenomena. 



The various pamphlets are reprinted word for word ; 

 and although the 'prentice hand is occasionally discern- 

 ible, yet in many cases where corrections or additions 

 have been rendered necessary these follow on immedi- 

 ately after the original article. Unfortunately some of 

 the typographical errors present in the original have 

 been reproduced, whilst others have here and there crept 

 in. The equations at the top of p. 271, vol. iii., for 

 example, are affected by both sources of error. 



In conclusion, we have only to remark that if short 

 notes giving a summary of contemporaneous work and 

 ideas from other laboratories had been interspersed 



